1. Field of the Invention
The present invention relates generally to methods of decorating cylindrical objects or items that can be supported on a cylindrical objects, wherein a heat transfer sheet comprising sublimable dyes is used in transferring desired images or other decorations to the cylindrical objects or other items supported on the cylindrical objects. The present invention relates in particular to methods of decorating metal cans used in the beverage and food packaging industries.
2. State of the Art
The use of heat transfer sheets which contain sublimable dyes for transfer of images and patterns to a substrate on which the heat transfer sheets are in contact is well known in the prior art. The image can be transferred from the transfer sheet to numerous substrate materials including anodized aluminum, plastic materials and textile fabrics. The transfer sheet must be held in contact with the item to be decorated while the transfer sheet is heated. The sublimable dyes pass from the transfer sheet to the item to be decorated and are absorbed or adsorbed on the surface of the item. Heretofore, the process has commonly involved a heated platen. The item to be decorated is placed on a base support, and the transfer sheet is placed over the item in contact therewith. The heated platen is then pressed down on the transfer sheet to heat the sublimable dyes and drive the dyes into the surface of the item being decorated.
Decoration of cans used as beverage and food containers has heretofore involved complex, expensive printing equipment. A coating of plastic material is usually applied to the external surface of the can and the can then passes through a complex machine to have the decoration applied to the base coating. The equipment used is prone to malfunction and requires almost constant fine tuning of the mechanism for conveying and printing the images on the cans. The equipment used in forming the cans and applying the base coating of plastic material to the outside of the cans is much more reliable than the printing machines. It would be highly desirable to develop a process for printing the designs on the cans which is as reliable as the process for forming the cans so that the printing step is not a bottle neck forcing unnecessary shutdowns of the can forming process.
3. Objectives
A principal objective of the invention is to provide a novel, method of printing designs on cylindrical items such as cans used in the beverage and food industries, wherein the method comprises heat transfer printing of designs to the surface of the cylindrical items.
An additional objective of the invention is to provide such a method of printing designs on cylindrical items wherein separate, individual casings are readily applied to respective items to be decorated to hold the heat transfer sheet in contact with the surface of the item to be decorated.
Another objective of the invention is to provide an economical, reliable method of printing designs on cylindrical items wherein the method utilizes reliable mechanical apparatus which requires minimal maintenance and virtually no fine tuning as is required by conventional apparatus used in printing designs on cylindrical items such as cans.